"There is no story mode per se," Mitchell said. "You go through training, where you get to experience different operators and their devices. You can play against enemy AI in co-op through all the maps. You can customize matches, so that’s what we’re offering on the single-player side of things."

Games played in these training and co-op battles will still contribute progress toward grinding out unlocks, so playing against the AI won't mean missing out on the game's content. Still, the move is nonetheless likely to disappoint many of the series' fans. To the extent that there is a single-player mode, it seems to exist only to provide training for the multiplayer mode, not to tell a self-contained story.

Of course, Rainbow Six: Siege is far from the only game to drop its single-player campaign. The new R6 game is in the same boat as Star Wars: Battlefront and, for owners of the Xbox 360 and PlayStation 3, Call of Duty: Black Ops 3. Last year's Titanfallsimilarly eschewed a single-player campaign, as did Evolve earlier this year.

I suppose it is not tremendously surprising. A first-person campaign may last only a dozen hours, compared to what's often hundreds of hours sunk into multiplayer. The comments posted underneath reviews of the single-player portions of these games make it immediately (and often quite abrasively) clear that many of the people buying the games do not have any interest in the single-player aspect. If many or most of the people buying a game will spend most or all of their time in the multiplayer mode, then the value of a single player game may well be low.

Dropping single player will almost inevitably lead to lost sales from players who actually do pick up these games to shoot their way through a story, some of whom have no interest in multiplayer at all. But it's easy to imagine the revenue from those customers being less than the cost of developing a single-player mode—a cost that includes map design and creation, script writing, voice acting, direction, and so on and so forth. As a matter of pure economics, it's not altogether surprising that single-player campaigns get cut.

Nonetheless, it is disappointing. I play single-player campaigns in shooters. I enjoy them. They provide an experience that the multiplayer game does not, and cannot, rival.

Part of this is trivial. The undesirable aspects of multiplayer gaming with strangers—the racism, the homophobia, the flaming, the temper tantrums, and deliberate attempts to make your own team lose the game—are by now well established and widely known. Even as an avid multiplayer gamer, it's understandable that some may not want to dip their toes into that particular cesspool (or at least take the occasional break from it). This is especially true in a game like Rainbow Six where cooperation and communication within the team are essential, and this is a concern that's already being raised in the beta.

The single-player experience is also resistant to poor, and even nonexistent, Internet connections. It's simply a more reliable, consistent experience.

But much more than that, there is the game experience itself. Nothing I've ever done in multiplayer provides the same kind of memorable thrill as sneaking around the ruins of Pripyat in my ghillie suit to snipe at bad guys in Call of Duty: Modern Warfare. The fact that it was scripted, that the interactions between me and the enemies were planned, and that I wasn't going to be accosted by some teenager bunny hopping around the corner with dual-wield shotguns greatly enhanced the experience. It helped ratchet up the tension and meant that the moves that I made mattered.

The entire campaign of the oft-overlooked Medal of Honor reboot in 2010 conveyed a great sense of being trapped, surrounded by hostile forces, with our backs against the wall. There was a kind of pressure, a sense of danger that the multiplayer game never provides. The campaign was taut and thrilling precisely because it was scripted.

Even more open-ended, open-world campaigns can offer things that competitive multiplayer cannot. The death of Bloodwing in Borderlands 2 was an emotional moment. When I played the first Borderlands, Mordecai was my first and main character, giving his pet's death in the sequel a significance that has no counterpart in the multiplayer shooter. (Borderlands can of course also be played cooperatively, but it remains story-driven, with no true competitive multiplayer mode.)

In giving up story-driven campaigns, developers are forsaking the ability to create these kinds of long-lasting memories and emotional variety. They're also sacrificing the ability to create a certain kind of shared experiences. Many of you will recognize reference to All Ghillied Up, because you've played it yourselves and have similar experiences. These campaign missions give a shared experience—much like that offered by a film or a TV show—that can be talked about, enjoyed, dissected, and remembered long after they've been played.

The loss of these single-player campaigns, particularly in series like Rainbow Six, is something to be mourned. That crafted stories are being partially replaced by AI bots is in many regards the worst of all worlds; those bots lack both the challenge and behavior of real human enemies, while still not offering the variety and involvement that scripted, structured campaigns can achieve. Campaigns may not have been important to everyone, but Rainbow Six: Siege has, by ditching its campaign, lost at least one sale. I was previously excited to try the game. But now, I probably won't bother.

This may be a win for accountancy. I don't feel it's a win for gaming.